The main goals of this Core are to develop methods for analyzing relationships between exposure and host factors in the disease response and to assist other Center members both within the Research Core and another Cores in the application of the statistical methodologies. Finally the Core includes as one of its objectives training of graduate students in modern statistical methods. Core members have long-standing, substantial support for their work primarily from NIH. Four large research projects are currently the focus of this Core. These include: time related factors in cancer epidemiology, methodologic research in genetic epidemiology, statistical methods and air pollution epidemiology and methods for dealing with exposure measurement error. In all cases, significant issues in study design, statistics and epidemiology are being addressed by the development of new approaches. All the issues being addressed in this work are related to human health consequences of exposure to environmental toxicants. The group meets weekly for reviews of recent activities and an informal seminar. Graduate students are included so they can discuss their work and receive feedback from the faculty. The external interactions are primarily with the Respiratory Effects Research Core. It appears that additional work is underway to tie together the respiratory Effects Exposure Assessment Research Core with the Molecular Biology and Sample Processing, and Biostatistics Facility Cores.